Longer-term fixed-rate mortgage deals are at their cheapest for six years for those who can stump up a sizeable deposit, it emerged this week as the RPI inflation level hit 4.4%.

Rates on five-year fixes have continued to edge down, and now start at 4.49%. Just over two years ago even the very best deals were 5.5%-plus – though go back to 2003 and you could get one for 3.75%.

With talk of a hung parliament and the possibility of interest rate hikes if inflation continues to rise, experts say it's an option well worth considering if you are looking for a mortgage now and are on a tight budget – or you want to protect yourself during political and economic uncertainty.

However, if your finances are not so tight a base rate tracker may still be the best option – particularly one allowing you to switch to a fixed-rate when rates start to move upwards.

Britannia and the Co-operative Bank are sitting on top of the Moneyfacts best-buy table with a new five-year fix at 4.49% until August 2015. However, it is only open to those borrowing a maximum of 75% of their property's value, and there is a £999 arrangement fee. Meanwhile, First Direct has a deal where you pay 4.54% for five years, plus £498 fees, though the minimum deposit is even bigger at 35%. The Newcastle and Chelsea building societies both have home loans with a 4.59% rate, a £995 fee, and a minimum deposit of 40% and 25% respectively.

These will be well out of the reach of many first-time buyers. "The best rate for someone with a modest deposit – 10% – is 6.69% from Yorkshire Bank, so those who can least afford it will end up paying the highest rates," points out Melanie Bien at mortgage broker Savills Private Finance.

She says that if you need the certainty of a fixed rate because you are on a tight budget, or prefer to know exactly how much your mortgage is going to cost each month, a five-year fix may make more sense than a two-year deal.

"While two-year fixes are cheaper, there is a strong possibility interest rates will be rising in two years, which means you will need to remortgage when rates are higher, so it is going to be more expensive.

"The advantage of a five-year fix is it will take you past that period, giving you peace of mind for longer and potentially proving to be better value."

Ray Boulger at mortgage broker John Charcol, says you can make a better case for a five-year fix today than a few weeks ago, particularly after the first TV leaders' debate, which sent the Liberal Democrats' stock soaring and increased the chances of a hung parliament. No overall majority could result in turmoil for the financial markets, which might push up interest rates.

He doesn't think the pricing of these deals will get much lower, but adds: "My gut feeling is that trackers will still work out cheapest." First Direct is offering a lifetime tracker at Bank of England base rate plus 1.89%, giving a pay rate of 2.39% (needless to say, it is only available to those borrowing a maximum of 65% of the property's value). That is much cheaper than even the most competitive five-year fix, and shows that, as things stand, there is still a big premium to pay for the security of a longer-term fix.

But, adds Boulger, "if you want to insure against the political risk, at least you can buy at the cheapest rates for about six years". And some lenders will allow you to switch from a tracker to a fixed rate (or vice versa) without incurring extra costs.

Bien says that for those who could afford to pay their mortgage if rates rise, then a base rate tracker might be a good option. She says that First Direct's lifetime tracker has the added advantage of no early repayment penalties, allowing you to hop on to another deal if rates start moving upwards.